Bagmaking machines

ABSTRACT

At the delivery end of a bagmaking machine, upper and lower endless belt conveyors are arranged to run face to face over a common portion of their respective paths. The beginning of this portion provides a nip which receives the bottom end of each bag in turn as it is ejected from the surface of a rotating drum. The bags are conveyed between the conveyors through their common portion and are delivered therefrom downwardly to a delivery station at which they are arrested. The conveyors are run more slowly than the drum so that the bags, which are spaced apart around the drum, overlap each other in a continuous shingled form when they pass through the conveyors. Thus, when arrested at the delivery station they from easily into a stack or wad of bags.

[4 1 Feb. 22, 1972 [54] BAGMAKING MACHINES [72] Inventor:

[73] Assignee:

Bruce lan Hayes, Bristol, England Beuley French & Company Limited,Bristol, England [22] Filed: Aug. 14, 1970 [21] Appl.No.: 63,801

[30] Foreign Application Priority Data Aug. 14, 1969 Great Britain.'...40,773/69 [56] References Cited UNITED STATES PATENTS 3,105,422,10/1963 Simpson et a1 ..93/93 DP Glahn ..27ll68 Berggracht ..93/93 DP UXPrimary Examiner-Bemard Stickney Attorney-Lackenbach 8L Lackenbach [57]ABSTRACT At the delivery end of a bagmaking machine, upper and lowerendless belt conveyors are arranged to run face to face over a commonportion of their respective paths. The beginning of this portionprovides a nip which receives the bottom end of each bag in turn as itis ejected from the surface of a rotating drum. The bags are conveyedbetween the, conveyors through their common portion and are deliveredtherefrom downwardly to a delivery station at which they are arrested.The conveyors are run more slowly than the drum so that the bags, whichare spaced apart around the drum, overlap each other in a continuousshingled form when they pass through the conveyors. Thus, when arrestedat the delivery station they from easily into a stack or wad of bags.

5 Claims, 3 Drawing Figures PAIENIEBFEB 22 m2 SHEET 1 OF 2 INVENTORLBRUCE IAN HAYES Attorneys PAIENTEDFEB 22 1912 sum 2' 0F 2 Inventor.

Attorneys BAGMAKING MACHINES This invention relates to bagmakingmachines.

In conventional bagmaking machinery, bags are made from a continuous webof sheet material; successive lengths of the web being cut off, foldedand glued (although not necessarily in that order) to form the bags,which are then collected and formed into wads or stacks. In one commonlyused form of bagmaking machine, in the last stage of the operation thebags, spaced apart in the direction of travel, are led bottom end firstonto a large rotating drum. Axially extending gripping means on the drumgrip the glued and folded-over bottom end portion of each bag in turnand cause it to be drawn around the drum. The bottom end portion isreleased and ejected (or stripped) from the drum at an ejection stationat a point on the drums periphery where the bag is moving downwards. Theintention is that the bag should then fall away from the drum to adelivery station platform, where successive bags build up a horizontallyextending stack.

This works well in practice at moderate deliver speeds with the smallersizes of bag and with heavier grades of sheet material. Recentlydeveloped high-speed machines have however shown a serious problem,particularly with larger bags and with the lighter weights of sheetmaterial, in that transverse folding and creasing tends to be producedperiodically in bags being delivered to the stack.

Investigations have shown that this folding and creasing may be due to avariety of possible causes. Firstly, the sudden arresting of the bottomof the faster moving bag at the delivery station produces greaterinertial forces in the remainder of the bag which may tend to causeflexing. Another possibility is that static electric or other adhesionproduced between the bags and the drum prevent efficient release of thebags at high speeds. Various other factors may be involved, but theproblem seems to be a function mainly of bag speed, bag length andmaterial weight.

The present invention seeks to provide, in bagmaking machines,improvements such as tend to overcome the stated problem.

According to the present invention there is provided for a bagmakingmachine, apparatus for collecting and stacking the bags, which includesupper and lower endless belt conveyors arranged to run face to face inthe same directionand at the same speed over a common portion of theirrespective paths, the beginning of said common portion providing a nipbetween the conveyors located adjacent the ejection station of the drumof the bagmaking machine so as to receive the ejected bottom end portionof each bag in turn, the lower conveyor where it extends beyond the endof said common portion being arranged to convey the bags downwardly to adelivery station, means being provided at the delivery station forarresting the bags and supporting a stack formed by successive deliveryof the bags from the lower conveyor, the conveyors being capable ofrunning at a speed sufficiently slower than the speed of the bags on thedrum such that successive bags overlap each other on the conveyors.

Preferably, at least the lower conveyor comprises a plurality of endlessbands running generally parallel to each other at the same speed.

Behind the portion of the lower conveyor run leading down to thedelivery station, suction means may be provided for holding the bags tothe conveyor. In front of the portion of the lower conveyor run leadingdown to the delivery station suction means may be provided for drawingthe trailing end portion of each bag away from the conveyor as the bagapproaches the delivery station.

In order that the invention may be more clearly understood, a preferredembodiment will now be described with reference to the accompanyingdiagrammatic drawings, wherein:

FIG. 1 shows in side elevation a part of a bagmaking machineincorporating the improvement of the present invention,

FIG. 2 shows a section on the line IIll of FIG. I, omitting the bagsupport fingers and transfer arms, and

FIG. 3 shows in longitudinal cross section the reciprocating armmechanism.

Referring to the drawings, bags are made in a conventional manner inthe'first part of the bagmaking machine (not shown) and are presented,bottom end portion 12 leading, to a large revolving drum 14. Thefolded-over and glued bottom end portion 12 of each bag is gripped inone of three axially extending gripping slots 16 provided in the drum14. The slots 16 are equally spaced around the drum, and the distancebetween them is greater than the length of each bag. The drum revolvesin the direction of the arrow A drawing each bag around until it ismoving generally vertically downwards, when each gripping slot, onarriving at an ejection station 18, releases the bottom end portion 12of its bag. Stripper tongues 20 are arranged at the ejection station;each stripper tongue sliding in a groove 21 in the drum, and having aramp-shaped surface 22 which causes the end portion 12 of the bag to bestripped from the surface of the drum [4.

In previously known machines, a horizontal platform has been arranged atthe ejection station to arrest the stripped bottom ends of the bags andsupport a horizontally extending stack formed by the ejection ofsuccessive bags. In the present embodiment however, the stripped endportions 12 are led by means of the ramp surfaces 22 of the strippertongues 20 into a nip 24 formed between two continuously moving endlessbelt conveyors 26, 28.

The upper conveyor 26 comprises a pair of parallel conveyor bands 30passing around four rollers 32, 33, 34 and 35. The lower conveyor 28comprises three pairs of parallel conveyor bands 36. These bands 36 passaround four rollers 38, 39, 40, 41. The upper and lower conveyors arearranged tolbe driven at the same speed in the direction shown by thearrows B. 1

The belts of both conveyors 26, 28 pass over the rollers 32,

35, 39 and 40, thereby providing a common portion over which theconveyors run face to face in the same direction and at the same speed.The beginning of this common portion, where the two sets of beltsconverge, provides the nip 24 for receiving the bottom end portions 12of the bags. The bags thus received are drawn between the two conveyorsthrough this common portion.

The portion of the lower conveyor 28 extending beyond the end 46 of thiscommon portion travels vertically downwards. Behind the lower conveyorin this portion there is located a grill 47 of vertical bars throughwhich three suction ducts 48 are arranged to apply suction through eachof the three pairs of bands 36. The effect of this is that the bagsemerging from the end 46 of the common portion of the conveyors are heldby the suction to the lower conveyor bands.

Just below the suction ducts the bags are arrested at a deliverystation. At the delivery station, a pair of parallel transfer arms 51are hinged at 53 so as to be movable between a horizontal position,shown in full lines in FIG. I, in which they extend through the lowerconveyor between the bands 36, and a depending position, shown in brokenlines in FIG. 1. Each transfer arm has a sliding upwardly cranked member55, operated by a pneumatic cylinder 57 so as to cooperate with a fixedupstanding part 59 in providing on the arm a pair of jaws for gripping astack or wad of bags. From the other side of the lower conveyor at thedelivery station a pair of parallel reciprocating arms 61 are arrangedfor movement through the conveyor between the bands; this movement beinglinked to the pivotal movement of the transfer arms so that thereciprocating arms project through the conveyor when the transfer armsare removed from the horizontal position. Thus, the downwardlytravelling bags are arrested by engagement of their leading ends 12 witheither the sliding members 55 of the transfer arms or with thereciprocating arms 61, and a stack or wad 54 is built up. The stack issupported horizontally by resilient support fingers 50.

As shown in FIG. 3, each reciprocating arm comprises two relativelyslidable parts 63 and 65. The lower part 65 has an upwardly cranked rearend portion 67 through which a screw 69 extends into the rear end of theupper part 63. The screw carries three nuts 71, by means of which, andin cooperation with the head 73 of the screw, the extent of relativesliding movement between the two parts can be accurately adjusted. Theleading endof the upper part 63 is slotted at 75, and a claw 77 ispivoted at 79 in the slot. The claw has a depending tongue 81 whichengages in a slot 83 in the lower part 65, so that relative slidingbetween the two parts causes movement of the claw between a retractedposition, shown in full lines, and an extended position, shown in brokenlines. A pinion 85 engages in a rack 87 formed on the underside of thepart 65 for reciprocating the arm. Thus forward movement of the pinionfirstly extends the claw and then moves the arm forward as a whole;reverse movement of the pinion from the forward posi-- tion of the armfirstly retracts the claw and then withdraws the arm as a whole.

When the arms 61 are extended through the conveyor, the ends of theclaws abut the existing stack of bags and cuts it off from the followingbags which are then arrested by engagement with the upper parts 63 ofthe arms. The transfer arms, by operation of their pneumatic cylinders,have by this time gripped the lower end of the existing stack, and bypivoting downwardly withdraw the stack to a horizontal position on acontinuously moving conveyor 89. The transfer arms move through a set ofvertically reciprocating cranked fingers 91 arranged at the far side ofthe conveyor 89 so as to arrest and grip the stack and thus remove itfrom the grip of the transfer arms, which then return to the horizontalposition to collect another stack. M

The rate of travel of the conveyors 26, 28 is relatively slower thantherate of travel of the bags in the bag making machine up to andincluding the drum 14. Thus, although the bags are spaced apart on thedrum 14, as a result of their being slowed down on entering the nip 24between the conveyors, they are caused to overlap to a considerableextent and form an unbroken shingled line of bags through the conveyors.For example, the conveyors may be run at rather less than half the speedof the rest of the machine so that successive bags overlap each other byabout half their length. The advantages of this arrangement are thatfirstly, only a part of each bag is in contact with each conveyor, andthe adhesive effect between bag and conveyor arising from any staticelectricity is proportionately reduced. Secondly, the overlapping of thebags prevents the bottom of one bag engaging the top of the precedingbag at the delivery station. In addition the area of one bag slidingover the next, the frictional effect of which may assist in causing theundesirable transverse flexing, is halved at each station, and the speedof relative sliding is also halved. Conveniently, the conveyors may bedriven by gearing to the roller 14. The gearing may be adjustable sothat the overlap of the bags can be controlled and different sizes ofbags accommodated.

Since the trailing end portion of each bag overlaps the following bag,it will not be directly exposed to the suction of the ducts 48. Anapertured roller 93 is arranged for rotation about a horizontal axis infront of the lower conveyor near the upper end of the stack of bags.Internally the roller is divided into two stationary compartments; asuction compartment 95 near the conveyor, and a blower compartment 97remote from the conveyor. The roller rotates in the direction of thearrow C, and therefore the trailing end portion of each bag is suckedaway from the conveyor and drawn around under the roller where it isthen blown away from the roller. In this way, the bags are drawnawayfrom the conveyor as they approach the delivery station, and thisgreatly helps in slowing them down and reducing their frictional andinertial forces on being arrested.

Further general advantages of the present invention may be stated asfollows. The relatively slower speed of the conveyors reduces theinertial forces in the bags when they are arrested by the platform 52 atthe delivery station. By providing conveyors consisting of parallelbelts with relatively much larger spaces between them, the efi'ect ofstatic electric adhesion between the bags and conveyors lS greatlyreduced. The same effect might alternatively be produced by'employing asingle openwork web belt for at least the upper conveyor.

What I claim and desire to secure by Letters Patent is:

1. For a bagmaking machine, apparatus for collecting and stacking thebags, which includes upper and lower endless belt conveyors arranged torun face to face in the same direction and at the same speed over acommon portion of their respective paths, the beginning of said commonportion providing a nip between the conveyors located adjacent theejection station of the drum of the bagmaking machine so as to receivethe ejected bottom end portion of each bag in turn, the lower conveyorwhere it extends beyond the end of said common portion being arranged toconvey the bags downwardly to a delivery station, means being providedat the delivery station for arresting the bags and supporting a stackformed by successive delivery of the bags from the lower conveyor, theconveyors being capable of running at a speed sufi'lciently slower thanthe speed of the bags on the drum such that successive bags overlap eachother on the conveyors.

2. Apparatus according to claim 1 wherein at least the lower conveyorcomprises a plurality of endless bands running generally parallel toeach other at the same speed.

3. Apparatus according to claim 1 wherein, behind the portion of thelower conveyor run leading down to the delivery station, suction meansare provided for holding the bags to the conveyor.

4. Apparatus according to claim 1 wherein in front of the portion of thelower conveyor run leading down to the delivery station, suction meansare provided for drawing the trailing end portion of each bag away fromthe conveyor as the bag approaches the delivery station.

5. Apparatus according to claim 1 wherein there are provided in theregion of the delivery station first and second arms, each movable intoand away from a position wherein it can arrest the bags and support thestack, the first arm being also adapted for gripping and removing thestack of bags, the movement of the two arms being linked so that whenthe first arm grips and removes a stack of bags the second arm arreststhe following bags and supports them until the return of the first arm.

1. For a bagmaking machine, apparatus for collecting and stacking thebags, which includes upper and lower endless belt conveyors arranged torun face to face in the same direction and at the same speed over acommon portion of their respective paths, the beginning of said commonportion providing a nip between the conveyors located adjacent theejection station of the drum of the bagmaking machine so as to receivethe ejected bottom end portion of each bag in turn, the lower conveyorwhere it extends beyond the end of said common portion being arranged toconvey the bags downwardly to a delivery station, means being providedat the delivery station for arresting the bags and supporting a stackformed by successive delivery of the bags from the lower conveyor, theconveyors being capable of running at a speed sufficiently slower thanthe speed of the bags on the drum such that successive bags overlap eachother on the conveyors.
 2. Apparatus according to claim 1 wherein atleast the lower conveyor comprises a plurality of endless bands runninggenerally parallel to each other at the same speed.
 3. Apparatusaccording to claim 1 wherein, behind the portion of the lower conveyorrun leading down to the delivery station, suction means are provided forholding the bags to the conveyor.
 4. Apparatus according to claim 1wherein in front of the portion of the lower conveyor run leading downto the delivery station, suction means are provided for drawing thetrailing end portion of each bag away from the conveyor as the bagapproaches the delivery station.
 5. Apparatus according to claim 1wherein there are provided in the region of the delivery station firstand second arms, each movable into and away from a position wherein itcan arrest the bags and support the stack, the first arm being alsoadapted for gripping and removing the stack of bags, the movement of thetwo arms being linked so that when the first arm grips and removes astack oF bags the second arm arrests the following bags and supportsthem until the return of the first arm.